Catalytic hydrocracking with the use of a silica-zirconia composite



United States Patent CATALYTIC HYDROCRACKING WITH THE USE OF ASILICA-ZIRCONIA COMPOSITE Charles J. Plank, Woodbury, and Edward J.Rosinski,

Almonesson, N.J., assignors to Socony Mobil Oil Company, Inc., acorporation of New York No Drawing. Filed Jan. 6, 1960, Ser. No. 703Claims. (Cl. 208-410) This invention relates to the catalytic conversionof hydrocarbons and to an improved catalyst for effecting saidconversion. More specifically, the invention is concerned with catalytichydrocracking of hydrocarbon oils in the presence of a new and improvedcatalyst. In one embodiment, the invention is concerned with an improvedhydrocracking catalyst consisting essentially of at least one componentcharacterized by dehydrogenation activity deposited on a particularlyprepared silica-zirconia base. In another embodiment, the invention isdirected to an improved method for preparing the aforesaid catalystuseful in catalytic cracking of heavy petroleum fractions in thepresence of hydrogen to lighter materials boiling in the gasoline range.

As is well known, cracking refers generally to operations wherein a longchain hydrocarbon Or a mixture of high molecular weight hydrocarbons isconverted into a shorter chain hydrocarbon or into a mixture of lowermolecular weight hydrocarbons. Cracking, accomplished solely as a resultof the high operational temperature employed, is known as thermalcracking while cracking effected in the presence of .catalysts isordinarily known as catalytic cracking. Cracking carried out in thepresence of hydrogen is referred to as hydrocracking,

Catalytic cracking of petroleum hydrocarbons has heretofore been carriedout at temperatures in the range of 800 to 1100 F. Such hightemperatures have been inefiicient from an economical standpoint andundesirable from an operational standpoint resulting in the productionof unwanted coke, relatively large amounts of dry gas and excessquantities of C hydrocarbons. The production of coke and dry gasrepresents a loss thereby bringing about an overall decrease in theyield of useful cracked product.

As is well known, charge stocks heretofore employed in catalyticcracking operations have been selected petroleum stocks. Thus, heavyresidual stocks as well as cycle stocks obtained from catalytic crackingof known refractory petroleum cracking stocks have not been suitable forcatalytic cracking processes because of their inherent coke-formingcharacteristics and the excessive amounts of dry gas produced.Accordingly, the supply of available cracking stocks has been somewhatrestricted.

Cracking operations carried out in the presence of hydrogen atrelatively high temperatures and under elevated pressures, i.e.hydrocracking, do not impose the aforesaid limitations on the type ofuseable charge stock. Thus, cycle stocks, heavy residuals etc. canbecracked in hydrocracking operations. Conventional operations of thistype, however, have many disadvantages. Thus, in order to maintaincatalyst activity at a desired level and to avoid a heavy deposition ofcoke on the catalyst, it has been necessary to employ excessively highhydrogen pressures of the order of at least about .3000 pounds persquare inch and preferably much higher.

3,067,127 Patented Dec. 4, 1962 There is accordingly, at the presenttime, great interest in the petroleum industry in developing a moderatepressure hydrocracking process. This interest arises from the ability ofhydrocracking to substantially increase both the quantity and quality ofnaphtha and fuel oil that a petroleum refinery can produce from crudeoil. These advantages have been amply demonstrated by the aforementionedhigh pressure hydrocracking operations. The high cost of high pressurehydrocracking necessitating the use of expensive high pressure equipmenthas prevented its widespread use, hence the necessity in develop ing aless expensive moderate pressure process which will retain many of thedemonstrated advantages but at acceptable cost.

In accordance with the present invention, it has been discovered thatcracking of hydrocarbons in the presence of hydrogen and a particularcatalyst permits the use of appreciably lower reaction temperatures andpressures. Thus, it has been found that cracking of hydrocarbons can beeifected in the presence of hydrogen and in the presence of a catalystcomprising a particularly prepared support consisting essentially ofsilica and zirconia and having impregnated thereon a minor proportion ofa dehydrogenation component. Such catalyst employed in the process ofthe invention has been found to afford a highly favorable distributionof products of high quality. The process described herein has thefurther advantage of being applicable for catalytic hydrocracking a widevariety of charge stocks including heavy residual and refractory chargestocks.

The present invention provides a process for hydrocracking ahydrocrackable material by contacting the material to be hydrocrackedand, particularly, a petroleum hydrocarbon fraction having an initialboiling point of at least about 400 F., a 50 percent point of at leastabout 500 F. and an end boiling point of at least about 600 F. andboiling substantially continuously between said initial boiling pointand said end boiling point with the above catalyst consistingessentially of particularly prepared silica-zirconia having depositedthereon a minor proportion of a component characterized bydehydrogenation activity in the presence of hydrogen at a hydrogenpartial. pressure between about and about 5,000 pounds per square inchgauge, a liquid hourly space velocity of between about 0.1 and about 10,a temperature between about 600 F. and about -0 F. employing a molarratio of hydrogen to hydrocarbon charge between about 2 and about 8-0.

We are aware that it has heretofore been proposed to convert hydrocarbonfractions in the presence of hydrogen and certain catalytic compositesconsisting essentially of a cracking component of silica combined withalumina, zirconia, magnesia and the like, Which has undergoneimpregnation with a minor proportion of a dehydrogenation component suchas platinum, molybdena, etc. The hydrocracking process described hereinis distinguishable from such prior processes in that the silica-zirconia'base uponwhich the dehydrogenation component is deposited is preparedin accordance with a particular procedure which has been found toresult, after the aforesaid impregnation, in a more active, stable andselective hydrocracking process.

Thus, catalysts heretofore proposed for hydrocracking operations haveconsisted almost entirely of active hyonds.

drogenating components dispersed on an existing active cracking basesuch as platinum on silica-alumina, molybdena on silica-alumina, or ofsupported metal oxides or sulfides that have, to varying degrees, bothhydrogenating and cracking activity such as nickel sulfide on alumina,tungsten disulfide on clay and the like. Neither of the above typecatalysts has proven satisfactory for moderate pressure hydrocracking.When tested, these catalysts have shown a lack in one or more of thefollowing: the ability to retain activity during use; a good balancebetween cracking and hydrogenating activities; or the recovery ofactivity when carbonaceous products are removed after a period of use.

Following the teachings of this invention, it has been found that highlyeffective catalysts for use in moderate pressure hydrocracking can beobtained by impregnation of a dehydrogenation component on a compositeof silica and zirconia which has been prepared by reacting awater-soluble zirconium compound and an alkali metal silicate to elfectformation of a gelable sol consisting essentially of silica and zirconiacharacterized by a pH in excess of 6 and a zirconia content, on a drysolids basis, of between about 2 and about 20 percent by Weight,permitting the sol to set forming a silica-zirconia gel, reducing the pHof the gell to below 5 and activating the same by maintaining the gellunder such conditions of reduced pH while in contact with an aqueousmedium at a temperature in the approximate range of 150 to 220 F. for aperiod of at least about 1 hour under conditions of substantiallyatmospheric pressure, thereafter washing the gel free of soluble matter,drying and calcining. A catalyst prepared in accordance with theforegoing procedure *the activation step of treating the silica-zirconiagel in an aqueous medium at the specified conditions and the control ofpH during gelation and such activation step are essential in achievingthe usually effective activity, stability and selectivity characterizingthe catalyst described herein. It has been found, in accordance with thepresent invention, that not only is the activation step essential butthat also the conditions required during this step to obtain theabove-described desirable catalyst properties are very critical. Thus,the pH during the activation step is essentially below 5 and preferablybelow 3. The pH of gel formation, on the other hand, is essentiallyabove 6 permitting the attainment of silicazirconia gels characterizedby particularly favorable gel properties as well as by a short time ofset, i.e. generally less than 2 hours and more particularly, less than20 sec- Hydrogels prepared at a pH above 6 are much more susceptible toactivation than those prepared below 6 pH. The temperature of theactivation treatment involving the use of an aqueous medium is aboveabout 150 F. and preferably above 175 F. and generally does not exceed220 F. The time required for activation is generally at least 1 hour andmay extend up to 48 hours or longer. Preferably, the activation periodis at least 2 hours and usually in the approximate range of 2 to 24hours.

The intermediate hydrogel state obtained in preparation of presentcatalysts is to be distinguished from a gelatinous precipitate. Trueall-embracing hydrogels occupy the entire volume of the solution fromwhich they are formed and possess a definite rigid structure. Whenfracany substance.

reduce the hydrogel pH to less than 5.

free of soluble impurities due to the tendency of gelatinousprecipitates to peptize on washing. A distinct and further advantage ofhydrogels is that due to their rigid structure, they can be formed intohigh quality spheroidal particles.

The zirconium compound employed in the present process is awater-soluble compound and suitably a watersoluble mineral acid salt ofzirconium such as, for example zirconium nitrate; zirconium sulfate andzirconyl chloride. Of this group, zirconium sulfate is accordedpreference. Zircon sand is a suitable source of zirconium compound. Thezirconia content of such sand can be converted to zirconium sulfatethrough caustic fusion at temperatures exceeding 1000 F. and subsequentleaching with sulfuric acid.

The silicate reactant is generally an alkali metal silicate andparticularly sodium silicate although silicates of the other alkalimetals such as for example, potassium silicate, might likewise beemployed. An organic silicate ester, for example ethyl orthosilicate mayalso be employed as the source of silica.

The solutions of zirconium compound and silicate reactant are intimatelymixed in such proportions as to yield a gelable sol having a zirconiacontent, on a dry basis, of between about 2 and about 20 and preferablybetween about 5 and about 15 percent by weight and a pH of above 6 andgenerally not exceeding about 10.

The resulting product is a hydrosol of silica and zirconia characterizedby an inherent capacity to set to a hydrogel upon lapse of a suitableperiod of time extending from a few seconds up to several hoursdepending on pH, temperature and solids concentration Without additionto or subtraction from the hydrosol of By following the above procedurethe time of gelation can be very rapid, i.e. less than 20 seconds, whichpermits the gel to be prepared directly in the form of spheroidalparticles resulting in a product of improved physical properties and indefinite economic advantages in the manufacture of the catalyst. In addition to afiording rapid gelation, the high pH of gel formation has beenfound to give rise to a more selective hydrocracking catalyst uponimpregnation with a dehydrogenation component as described hereinbelowas compared with a comparable silica-zirconia gel in which the pH offormation is below 6.

of time is permissible, it is generally desirable to reduce the pH ofthe silica-zirconia hydrogel shortly after formation to less than 5.Maintaining the hydrogel upon conditions of pH at which formation iseffected for a considerable period of time was found to be detrimentalto the selectivity of the finished catalyst. Generally, the hydrogel iscontacted with an aqueous solution of an acid or an acidic salt ofsufficient concentration to effectively Usually, an inorganic acid andparticularly a dilute solution of a mineral acid such as nitric,hydrochloric or sulfuric acid in the form of a 0.1 to 10 weight percentsolution is employed for this purpose. Salts such as sulfates, nitratesor chlorides of zirconium or aluminum can similarly be used.

The hydrogel of reduced pH is then activated by maintaining the sameunder the aforementioned conditions of reduced pH while in contact withan aqueous medium at a temperature in the approximate range of to 220 F.and more particularly, between about and about 220 F. at substantiallyatmosphericpressure for at least 1 hour and generally not exceedingabout 48 hours. This step is critical in achieving the desiredsilica-zirconia composite upon which a dehydrogenation component issubsequently deposited. In accordance with such step,

the hydrogel is suitably covered with an acidic solution to maintain thepH of the hydrogel during activation within the approximate range of 1to 5 and preferably 1 to 3. While the hydrogel after treatment to reduceits pH of formation as described may be transferred or conducted to anaqueous medium maintained at the elevated temperature specifiedhereinabove, it is generally preferred to effect activation of thehydrogel in the same solution used for reduction of pH. Thus, it iscontemplated that in a preferred operation the silica zirconia hydrogelafter formation at a pH in excess of *6 is conducted to an aqueousdilute solution of an acid or acid salt wherein the pH of the hydrogelis immediately brought to below 5 and the hydrogel is thereaftermaintained in such-solution at a temperature of between 150 and 220 F.for a sufficient period to accomplish the desired activation. The pH ofthe hydrogel during the activation treatment is an important factorhaving a direct bearing on the ultimate catalyst activity and, inaccordance with the process of catalyst preparation described herein,should be less than 5 and preferably below 3 in order to obtain acatalyst of high cracking activity.

After the activation treatment, exchangeable or zeolitic impurities, ifpresent, are removed from the hydrogel in any feasible manner. While asa practical matter all or a large proportion of such zeolitic impuritiesmay be removed during the course of the activation treatment with theaqueous medium containing an acidic compound, any remaining zeoliticmatter is suitably removed by base-exchange with aqueous solutions ofmineral acids such as hydrochloric and'sulfuric acids; solutions ofammonium salts which act to replace metal impurities with ammonium whichis later removed by calcining; and solutions of multivalent metal saltsparticularly a zirconium salt which may be the same or a differentzirconium salt from that employed in initial formation of the hydrogel.When base exchanging the silica-zirconia hydrogel with an acid a limitedand controlled amount must obviously be used to avoid redissolving thezirconia. When exchanging with ammonium compounds any excesses will becalcined out in the final steps of catalyst manufacture and when usingany zirconium or other multivalent metal salt which does not adverselyaffect the catalytic properties, excesses may be used and left on thecomposite.

After removal of zeolitic impurities the hydrogel is washed free ofsoluble excess ions. The resulting composite of silica and zirconia isdried in air or superheated steam at temperatures between about 200 andabout 400 F. for a period of between about 4 and 24 hours and/or bycalcining at a temperature between about 800 and about 1800 F. forapproximately 2 to 8 hours or more.

In some instances, it may be desirable to introduce into thesilica-zirconia hydrosol a quantity of solid powdered material insolubletherein having a weight mean particle diameter of between 1 and micronsand preferably be tween 2 and 4 microns. The amount of powdered materialso introduced is generally between about 2 percent and about 40 percentby weight and preferably between about and about 40 percent by weight ofthe dried gel product. The powder-containing silica-zirconia sol sets toa hydrogel after lapse of a suitable period of time and the resultinghydrogel is processed as described above and then dried to a gel at atemperature below the fusion point of the incorporated powder. It hasbeen found that a silica-zirconia gel resulting from the setting of asol containing powdered material of the aforementioned particle size anddrying of the resulting hydrogel at a temperature below the fusion pointof the added material has a substantially greater resistance toattrition and improved diffusivity as compared with the correspondingsilica-zirconia gels which do not contain such added powder. Thepowdered material may be added by dispersing in an already preparedhydrosolor as is preferable, when the hydrosol is characterized by ashort time of gelation, the powder may be added to one or more of thereactants used in forming the hydrosol or may be mixed in the form of aseparate stream with streams of the hydrosol-forming reactants in amixing nozzle or other means where the reactants are brought intointimate contact. In addition to having the above particle size, thepowdered solid incorporated into the silica-zirconia hydrosol shouldnecessarily be insoluble therein and should further be characterized bybeing infusible at the hydrogel drying temperature. The powderincorporated in the silica-zirconia sol maybe catalytically active or aninert material. As indicated hereinabove, the particular powderedmaterial to be incorporated in the hydrosol will be chosen so as to beinsoluble therein and to be infusible at the drying temperature.Observing these features, suitable representative materials having aweight mean particle diameter of 1 to 5 microns include gels orgelatinous precipitates such as those of silica, alumina, magnesia,chromia, molybdena, zirconia, thoria, titania and the like includingcomposites thereof. Thus, a particularly prepared powdered material forincorporation in the sol includes pulverized silica-zirconia fineshaving a weight mean particle diameter of l to 5 microns. Other suitablematerials include zircon sand (zirconium silicate) as well as othermetal silicates, metals and metal oxides including aluminum oxide,chromium trioxide, molybdenum oxide, magnesium oxide, manganese oxide,zirconium oxide and silicon oxide in their various forms andmodifications.

The silica-zirconia gel base may be prepared in any desired mechanicalform according to the specific purpose for which it is intended. Eitherbefore or after calcina tion, it can be broken into lumps or granules orit can be ground to a fine powder adapted for use in the suspensoid orfluidized-solids process. Alternatively, the catalyst can be formed intopills, pellets or other suitable shapes preferably prior to thecalcination step for use in the fixed bed or compact moving bedoperations. In this case, the catalytic mixture is partially dried,ground to a powder preferably smaller than 30 mesh (Tyler), combinedwith a suitable lubricant such as graphite, hydrogenated coconut oil,stearic acid, rosin or the like and shaped by extrusion, molding or byother means known in the art. Particles having dimensions ranging fromabout A x /s" to /2 x V2" are generally satisfactory. The shapedparticles can then be further dried and/or calcined as described above.

It is particularly desirable to prepare the silica-zirconia gel base inthe form of spheroidal bead-like particle's. For such purpose, theinitially prepared hydrosol is introduced in the form of globules to awater-immiscible 'fluid such as into a column of water-immiscibleliquid, for example an oil medium wherein the globules of hydrosol setto spheroidal bead-like particles of hydrogel. Larger size spheres areordinarily within the range. of from about to about /2 in diameter,whereas smaller size spheres which are generally referred to asmicrospheres are within the range of from about 10 to about microns indiameter. The use of spheroidal shaped gel particles is of particularadvantage in hydrocarbon conversion processes including the movingcatalyst bed process, the fluidized process and other processes in whichthe spheroidal catalyst particles are subjected to continuous movement.As applied to the stationary bed, spheroidal catalyst particles provideeffective contact between the reactants and the catalyst by avoidingchannel- The conventional cracking activity of a catalyst is generallyexpressed in terms of the percent by volume of a standard hydrocarboncharge which is cracked und'er specific conditions in the Cat-A test.The method of this test is described in National Petroleum News, 36 p.PR-537 (August 2, 1944), and the cracking activity "so seems? determinedis referred to as the activity index (A.I.). Accordingly, it will beunderstood that the term activity index when employed herein shall referto the cracking activity of the material under consideration determinedin accordance with the Cat-A method. The activity index of theabove-described silica-zirconia composites utilized herein as supportsfor a dehydrogenation component is preferably within the range of about25 to about 50.

A component exhibiting dehydrogenation activity is deposited on thesilica-zirconia gel prepared in accordance with the above-definedprocedure. Suitable dehydrogenation components include one or more ofthe metals of groups V, VI and VIII of the periodic table either inelemental form or in the form of the oxides or sulfides of these metals.Representative of these metals are molybdenum, chromium, tungsten,vanadium, cobalt, nickel and metals of the platinum group, i.e.platinum, palladium, rhodium, osmium, iridium, and ruthenium as Well ascombinations of these metals, their oxide-s or sulfides. Thus, aparticularly desirable combination of metal oxides is that of the oxidesof cobalt and molybdenum deposited on the hereinabove describedsilica-zirconia base. Deposition of one or more of the above-indicatedmetals may be in accordance with methods known to the art. For example,aqueous solutions of Water-soluble compounds of the desired metal may beemployed to impregnate the silica-zirconia composite. The resultingimpregnated composite is thereafter heated to convert the compoundemployed to the corresponding oxide which, if desired, may besubsequently converted to the metal sulfide. If the catalyst containsthe metal in elemental form, such as for example, metals of the platinumseries, the silica-zirconia base, after treatment, with a water-'soluble compound of such metal, may be subjected to treat- .ment withhydrogen to effect reduction of the metal to its elemental form.

Suitable molybdenum compounds employed in the present process forimpregnating the silica-zirconia base include ammonium molybdate,molybdenum tetrabromide, molybdenum oxydibromide, molybdenumtetrachloride, molybdenum oxydichloride, molybdenum oxypentachloride andmolybdenum oxytetrafluoride. Suitable cobalt compounds include cobaltnitrate, cobalt ammine nitrate, cobalt ammine chloride, cobalt amminesulfate, cobalt bromide, cobalt bromate, cobalt chloride, cobaltchlorate, cobalt fluoride, and cobalt fiuorate.

In one method the particles of silica-zirconia base are initiallysubjected to a vacuum to remove air from the pores thereof and Whilemaintaining the vacuum an impregnating solution such as describedhereinabove is brought into contact with the particles of thesilica-zirconia base. Alternatively, the silica-zirconia base may beimpregnated with a solution of more than one compound, for example asolution of a molybdenum compound and a cobalt compound. Also, separateimpregnating solutions of a molybdenum compound and a cobalt compoundmay be prepared and composited successively with the silicazirconia baseeither with or without an intervening heating of the support. Ingeneral, using this technique, it is preferred to composite themolybdenum component first and then the cobalt component although thereverse procedure may be employed. After the impregnation, the basematerial is dried and calcined to convert the metal compounds to theoxides.

When utilizing a metal of the platinum series as the dehydrogenationcomponent, one feasible method is to admix particles of thesilica-zirconia base with an aqueous solution of an acid of the metalfor example, chloroplatinic or chloropalladic acid or the ammonium saltof the acid of suitable concentration. It will be understood that anyother suitable source of platinum metal may be used. Chloroplatinic acidgenerally is preferred because it is more readily available. Solutionsof other feasible platinum-containing compounds include those ofplatinum ammine chlorides, trimethylbenzyl ammonium platinum 8 chloride,tetra-amminoplatino chloride, platinum ammine nitrate, dinitrol diamminoplatinum and the like. The particles of silica-zirconia impregnated witha platinum metal compound is then dried and treated with hydrogen atelevated temperatures to reduce the platinum metal compound to the metaland to activate the catalyst.

It will be appreciated that in addition to the foregoing, other suitablewater-soluble compounds of metals having hydrogenation-dehydrogenationactivity either in the metallic form or in the form of an oxide or asulfide may likewise be used. The particular amount of dehydrogenationcomponent composited with the silica-zirconia base will vary dependingupon the particular metal and the form in which such metal is employed.Thus, for composites containing a platinum metal, the amount of suchmetal contained in the catalyst will generally be between about 0.05 andabout 10 percent by weight and, more particularly, between about 0.1 andabout 5 percent by weight of the catalyst. The concentrations of thecobalt and molybdenum oxides in the catalyst described herein mayrespectively range from about 1 to about 10 percent by weight and fromabout 1 to about 20 percent by weight of the final catalyst. Whenchromia is employed as the dehydrogenation component, the contentthereof will generally be in the approximate range of 2 to 20 percent byWeight of the catalyst. When nickel is used, the metal content will bein the approximate range of 0.01 to 10 percent by weight of thecatalyst. Tungsten, when used as the active dehydrogenation component,should be present in the approximate range of 1 to 20 percent by weightof the catalyst.

After impregnation, the composite generally is dried at a temperature offrom about 200 F. to about 600 F. for a period of from about 2 to about24 hours or more and thereafter calcined at a temperature of from about600 F. to about 1300 F. for a period of from about 1 to 12 hours ormore. As noted hereinabove, When a metal of the platinum series isemployed as the dehydrogenation component, drying and calcination may besuitably carried out in a hydrogen atmosphere. In some instances, it isdesirable to prepare the dehydrogenation component in the form of ametal sulfide. In such case, the composite after the above-describedcalcination, may be suitably treated in an atmosphere of hydrogensulfide or a mixture of hydrogen sulfide and hydrogen at an elevatedtemperature such as for example about 800 F. In the case of tungstensulfide or nickel tungsten sulfide, the tungsten may be deposited on theammonium thiotungstate.

The hydrocracking process of this invention may be carried out in anysuitable equipment for catalytic operations. The process may be operatedbatchwise. It is preferable, however, and generally more feasible tooperate continuously. Accordingly, the process is adapted to operationusing a fixed bed of catalyst. Also, the process can be operated using amoving bed of catalyst wherein the hydrocarbon flow may be concurrent orcountercurrent to the catalyst flow. A fluid-type of operation whereinthe catalyst is carried in suspension in the hydrocarbon charge mayfeasibly be employed using the present catalyst.

Hydrocracking, in accordance with the present process, is generallycarried out at a temperature between about 600 F. and about 1050 F. andpreferably between about 700 F. and about 900 F. The hydrogen partialpressure in such operation is generally within the range of about 100and about 5000 pounds per square inch gauge and preferably about 1000and 3000 pounds per square inch gauge. The liquid hourly space velocityof fresh feed, i.e. the liquid volume of hydrocarbons per hour pervolume of catalyst is between about 0.1 and about 10 and preferablybetween about 0.25 and about 4. In general, the molar ratio of hydrogento hydrocarbon charge employed, i.e. fresh feed is between about 2 andabout and preferably between about 5 and about 40.

Hydrocarbon charge stocks undergoing cracking in accordance with thisinvention comprise hydrocrackable hydrocarbons mixtures of suchhydrocarbons and particularly hydrocarbon fractions having an initialboiling point of at least about 400 F., a 50 percent point of at leastabout 500 F. and an end boiling point of at least about 600 F. andboiling substantially continuously between said initial boiling pointand said end boiling point. Such hydrocarbon fractions include gas oils,residual stocks, cycle stocks, whole topped crudes, and heavyhydrocarbon fractions obtained by the destructive hydrogenation of coal,tars, pitches, asphalts, and the like. As will 'be recognized thedistillation of higher boiling petroleum fractions (about 750 F.) mustbe carried out under vacuum in order to avoid thermal cracking. Theboiling temperatures utilized herein, however, are expressed forconvenience in terms of the boiling point corrected to atmosphericpressure.

The hydrocracking selectivities of the catalysts described herein areevaluated by comparing their product distributions at fixed conversionlevels. The conversion is defined as -100 minus the volume percent ofcharge remaining in the 650 F.+ boiling range. The products consideredare dry gas (C -C 0.; material, light naphtha (C l80 F.), heavy naphtha(180390 F.), fuel oil (390650 'F.) and cycle stock (650 F.+). An overallmeasure of selectivity is the total yield of C -650 F. material at anyconversion level since this range contains the more valuable products.

The hydrocracking activity of a catalyst as this term is utilized hereinis defined as the temperature required to achieve a given conversionlevel.

The following examples will serve to illustrate the inventionhereinabove described without limiting the same:

Examples 1 and 2 demonstrate the catalytic differences between two typesof platinum silica-zirconia hydrocracking catalysts. The differencesinvolve the method of preparing the silica-zirconia bases. In Example 1the silica-zirconia base was formed above 6 pH and activated in hot acidwhile in Example 2 the silica-zirconia base was prepared by forming at3.6 pH and activated in a steam atmosphere. The details of such examplesare set forth below:

EXAMPLE 1 A catalyst of platinum on silica-zirconia was prepared byimpregnating a silica-zirconia cogel containing 12.7 percent by weightZrO (on a dry solids basis), formed at 8.9-9.4 pH and activated in 1percent by weight aqueous solution of H 80 for 24 hours at 175 -F., withchloroplatinic acid to yield 0.9 percent by weight platinum on thefinished catalyst.

The silica-zirconia base in this example was prepared in four batches bymixing, in each instance, 300 cc. of an aqueous solution of zirconiumsulfate [Zr(SO -4H O] containing 0.05 g. ZrO /ce, 35 cc. of 50 percentby weight sulfuric acid diluted with 1470 cc. of water and 700 cc. ofdiluted N-Brand aqueous sodium silicate solution containing 0.193 g. SiOcc. to yield a silica-zirconia hydrosol. The resulting sol set to a firmgel in 10-15 seconds having a pH of 8.9-9.4. This gel was cut into cubesand covered with a 1 weight percent aqueous solution of H 80 thuslowering the hydrogel pH to 1.7-2.0. Activation of the hydrogel wasaccomplished by heating in this solution for 24 hours at 175 F. Thehydrogel was thereafter base-exchanged with a 2 weight percent aqueousammonium chloride solution. The base-exchanged hydrogel was thenwater-washed free of chloride ion, dried for 16 hours at 280 F. in airand calcined 10 hours at 1200 'F. in air. The silica-zirconia gel baseso obtained was characterized by a pore volume of 0.46 cc./g.; anapparent density of 0.63 g./cc.; a surface area of 589 m. /g. and aweight composition of 0.01 percent Na; 0.17 percent S0 12.7 percent ZrOand remainder SiO Platinum was deposited upon the silica-zirconia baseby vacuum spray impregnating 107 grams of such base with 9.94 cc. of HPtCl solution, containing 0.096 g. Pt/cc., diluted to 87.5 cc. withwater. The resulting impregnated catalyst was wet aged 16 hours at 230F. in a covered container so that very little loss of water occurred.The aged particles were thereafter reduced with hydrogen for 2 hours at450 F. and 2 hours at 950 F. The finished catalyst had a density of 0.66g./cc.; a surface area of 512 m. /g. and contained 0.9 weight percentplatinum and 0.19 weight percent chlorine.

EXAMPLE 2 The catalyst of this example was prepared by impregnating asilica-zirconia cogel containing 9.7 percent by weight ZrO (on a drysolids basis), formed at 3.6 pH and activated in a non-drying steamatmosphere with chloroplatinic acid to yield 0.98 percent by weightplatinum on the finished catalyst.

The silica-zirconia base was prepared by mixing 1200 cc. of aqueouszirconium sulfate solution containing 0.05 g. ZrO /cc., 248 cc. 50percent by weight sulfuric acid, 5752 cc. of water and 2800 cc. ofdiluted N-Brand so dium silicate solution containing 0.193 g. SiO /cc.to yield a silica-zirconia hydrosol. The resulting hydrosol havinga pHof 3.6 gelled in 4 to 5 hours at a room temperature of approximately70-77 F. This hydrogel was then activated by subjecting to a non-dryingsteam atmosphere (200 F. wet bulb-220 F. dry bulb) for 2 hours. Thehydrogel was thereafter dried at 240 F. and then base-exchanged with a 2weight percent aqueous ammonium chloride solution. The base-exchangedhydrogel was then water-washed free of chloride ion, dried for 24 hoursat 275 F. in air and calcined 10 hours at 1000 F. in air. Thesilica-zirconia gel base so obtained was characterized by a pore volumeof 0.34 cc./ g. and a weight composition of 0.03 percent Na; 0.07percent S0 9.7 percent ZrO and remainder SiO Platinum was deposited uponthe above silica-zirconia base in the same manner as in Example 1 toyield a resulting catalyst containing 0.98 weight percent platinum and0.55weight percent chlorine.

EXAMPLE 3 The base for the catalyst of this example was prepared byforming a silica-zirconia hydrosol by admixture of reactant solutionsdescribed in Example 2. The resulting sol having a pH of 3.6, formed afirm hydrogel in 4 to 5 hours at a room temperature of approximately70-77" F. This hydrogel, after standing for 16 hours at the above roomtemperature, was cut into cubes and then activated by contacting withwater for 24 hours at F. The activated hydrogen was thereafter dried andprocessed in the same manner as in Example 2. The silica-zirconia gelbase so obtained was characterized by a surface area of 490 mF/g. and aweight composition of 0.06 percent 0.09 percent S0 11.0 percent ZrO andremainder Platinum was deposited upon the above silica-zirconia base inthe same manner as in Example 1 to yield a catalyst containing 0.55weight percent platinum and 0.17 weight percent chlorine.

The above catalysts of Examples 1, 2 and 3 were tested inhydrocracking'a charge of 650 F. to tar West Texas gas oil.Hydrocracking was carried out at a 1 liquid hourly space velocity and at2000 pounds per square inch gauge pressure, utilizing a hydrogen tohydrocarbon charge'mol ratio of about 40 corresponding to 14,500standard cubic feet of hydrogen per barrel of charge. Hydrogen and thecharge stock were mixed together at the above pressure, heated toreaction temperature and passed downward through a bed of the catalystcontained in the test unit. Hot effluent from the bottom of the catalystbed was cooled and separated at the pressure utilized in the unit intogas and liquid product streams. The liquid product stream was stabilizedat atmospheric pressure before being sampled for distribution andanalysis. The gas recovered from the high pressure separation and fromstabilizing the liquid product were sampled and analyzed. Activity ofthe catalysts was evaluated by operating the catalyst bed at atemperature level selected to convert 70 volume percent of the gas oilcharge to material boiling below 650 F. The results of such testing areset forth in Table I hereinbelow. Referring to this table, thesuperiority of the catalyst of Example 1 over that of Example 2 andExample 3 is clearly evident from the 813 F. reactor temperaturerequired for the 70 volume percent conversion, while the catalyst ofExample 2 was so inactive and unstable that 70 percent conversion couldnot be achieved even at the maximum reactor temperature of 980 F. Whilethe catalyst of Example 3 gave better results than that of Example 2, itlikewise was so unstable that 70 volume percent conversion could not beachieved even at a reactor temperature of 901 F. Such data clearlydemonstrate the advantages of high pH forming and low pH activation overlow pH forming and activation of the hydrogel in water. Thus, the baseprepared at low pH and activated with steam gave a very poor catalyst.The silica-zirconia base prepared at low pH and activated at such pH inwater was active and unstable, while the base prepared at a pH in excessof 6 and activated at a low pH was both active and stable.

Examples 4, 5 and 6 illustrate the catalytic advantages of the catalystutilizing the silica-zirconia gel prepared as described herein as thebase for molybdena-silica-zirconia hydrocracking catalysts.

EXAMPLE 4 A silica-zirconia cogel was prepared by mixing the followingreactants:

Solution A which consisted of 60 percent weight N- Brand sodium silicateand 40 percent weight water having a specific gravity of 1.206 at 80 F.

Solution B which consisted of acid-zirconium sulfate solution containing6.61 percent weight Zr(SO -4H O, 89.77 percent weight H O, 3.62 percentweight H 80, and having a specific gravity of 1.064 at 80 F.

Solution A was continuously mixed in a nozzle at a rate of 380 cc./min.with 416 cc./min. of Solution B. The resulting silica-zirconia hydrosolhaving a pH of 8.2-8.5 set to a hydrogel in 2 seconds at 63 F. The solwas formed into spheroidal hydrogel beads by introducing globules of thesol into an oil medium. The resulting hydrogel beads were then treated24 hours at 200 F. in 2 percent aqueous H 80 solution which reduced thehydrogen pH to 2.0. The acid-activated hydrogel was thereafterbase-exchanged, washed and dried as in Example 1 and then calcined 20hours at 1000 F. in air. The silica-zirconia gel base so obtained wascharcterized by a pore volume of 0.44 cc./g.; an apparent density of0.84 g./cc.; a surface area of 627 m. g. and a weight composition of0.04 percent Na; 0.10 percent 80;; 11.0 percent ZrO and remainder SiOMolybdena was deposited upon the silica-zirconia base by vacuum sprayimpregnating 138 grams of such base in the form of 554 mesh sizeparticles with 10 percent M as a Water solution of molybdic acid. Thisimpregnated sample was then dried at 230 -F. and calcined 3 hours at1000 F. in air. The composite, so obtained, was sulfided With 50 percentH 0 percent H 5 mixture employing 2 volumes per volume of catalyst perminute for 5 hours at 800 F. The finished catalyst had a density of 0.71g./cc., a surface area of 438 mP/g. and contained 6.25 weight percentmolybdenum and 2.91 weight percent sulfur.

12 EXAMPLE 5 A silica-zirconia base, containing 9.7 weight percent ZrOwas prepared as in Example 4 in the form of hydrogel beads. Such beadswere then aged at room temperature for 2 hours followed by aging in 1percent aqueous H solution at 178184 F. for 24 hours, resulting in afinal pH of 2.4-4.2. The acid activated hydrogel was processed andcalcined as in Example 4. The silica-zirconia gel base so obtained wascharacterized by a pore volume of 0.55 cc./g.; an apparent density of0.60 g./cc.; a surface area of 523 m. /g.; and a weight composition of0.03 percent Na; 0.10 percent S0 9.7 percent ZrO and remainder SiOMolybdena was deposited upon the above silica-zirconia base in the samemanner as employed in Example 4. The resulting composite had a densityof 0.71 g./cc.; a surface area of 384 m. g. and contained 6.66 weightpercent molybdenum. Prior to testing, the catalyst Was treated with anequal volume mixture of hydrogen and hydrogen sulfide using theprocedure employed in Example 4. After this treatment, the sulfurcontent of the catalyst was 4.31 percent by weight.

EXAMPLE 6 The silica-zirconia based used in preparing the catalyst ofthis example was made in a manner identical with that used in preparingthe base of Example 2.

The silica-zirconia base so prepared was impregnated with M00 as a watersolution of molybdic acid in the same manner employed in Examples 4 and5. The resulting catalyst had a surface area of 394 mF/g. and amolybdenum content of 7.06 weight percent. Prior to testing thecatalyst, it was treated with an equal volume mixture of hydrogen andhydrogen sulfide in the manner used in Examples 4 and 5. After thistreatment, the sulfur content of the catalyst was 1.09 percent byweight.

The above catalysts of Examples 4, 5 and 6 were tested for hydrocrackingusing the charge stock and conditions described hereinabove inconnection with the testing of the catalysts of Examples 1, 2 and 3. Theresults obtained are set forth in Table I hereinbelow. Comparing theproperties of these catalysts, it will be seen that the catalysts ofExamples 4 and 5 prepared from a hot acid activated silica-zirconiahydrogen are much superior in activity and selectivity to the catalystof Example 6. Thus, reactor temperatures of 812 and 822 F. wererespectively required in Examples 4 and 5 to hydrocrack the specifiedgas oil charge to produce 70 volume percent products boiling between and650 F. The catalyst of Example 6, on the other hand, at 950 F. gave onlya 25 volume percent conversion to products boiling below 650 F.

The following example illustrates that an active and selectivehydrocracking catalyst can be prepared using combined dehydrogenationcomponents such as M00 and C00 on a silica-zirconia base prepared inaccordance with method described herein.

EXAMPLE 7 A silica-zirconia base containing approximately 11 percent byweight ZrO was prepared by reacting 320 cc. of aqueous zirconium sulfatesolution containing 0.05 g. ZrO /cc., 27 cc. of 50 percent by weightsulfuric acid, 1476 cc. of Water and 700 cc. dilute N-Brand sodiumsilicate. The resulting silica-zirconia hydrosol set to a firm hydrogelin 30-50 seconds having a 6.36.8 pH. This gel Was aged for 24 hours inwater at room temperature, and then for 48 hours at 200 F. in /2 percentaqueous sulfuric acid solution reducing the pH of the hydrogel to 2.6.The hydrogel was thereafter base-exchanged, water Washed and dried as inExample 1 and then calcined for 13 hours at 1000 F. in air. Thesilica-zirconia gel base so obtained was characterized by a pore volumeof 0.54 cc./g.; an apparent density of 0.63 g./cc.; a surface area 13 of597 m.*/ g. and a weight composition of 0.01 percent Na, 0.0l percent S11.1 percent ZrO and remainder SiO Hydrocracking catalyst was preparedby first vacuum spray impregnating the above silica-zirconia gel with 10percent M00, as a water solution of ammonium molybdate[(NH4)6MO7O24'4H2O], drying at 220 F. for 16 hours and calcining 3 hoursat 1000 F. in air. The resulting composite was then impregnated with 3percent CoO as a water-solution of cobalt nitrate dried at 230 F. for 3hours and calcined 10 hours at 1000 F. in air. The resulting catalystwas sulfided with a 50 percent H 50 percent H 8 mixture employing 2volumes per volume of catalyst per minute for 5 hours at 800 F.

The resulting catalyst was tested as above and the results are shown inTable I hereinbelow. This catalyst, as will be evident from the resultsof such table showed good hydrocracking activity, requiring a reactortemperature of 823 F. to hydrocrack the gas oil charge to 70 volumepercent of l00-650 F. products. The selectivity of this catalyst wasalso good showing 3.5 weight percent dry gas, 111.5 volume percent Cproducts, heavy naphtha/ fuel oil ratio of 0.76 and a fuel oil dieselindex of 41.

Examples 8 and 9 respectively illustrate the preparation ofhydrocracking catalysts of silica-zirconia base impregnated with theoxides of cobalt and molybdenum and with platinum wherein the base ischaracterized by a high diffusivity as a result of the inclusion ofground zircon sand in the initial hydrogel-forming reaction mixture.

EXAMPLE 8 weight mean particle diameter of 5 microns,.and 23 percentweight water.

Solution B which consisted of acid-zirconium sulfate solution containing6.6 percent weight Z-r(SO -4H 0, 89.7 percent weight H 0 and 3.7 percentweight H 50 Solution A was continuously mixed in a nozzle at a rate of356 cc./min. with 386 oc./ min. of Solution B. The resultingsilica-zirconia hydrosol having a pH of 7.6-7.9 set to a hydrogel: in2-2.7 seconds, at 71 F. The sol was formed into spheroidal hydrogelbeads by introducing globules of the sol into an oil medium. Theresulting bead. hydrogel containing, on a dry solids basis, 10 percentby weight cogelled zinconia while the 40 weight percent zircon powdercontributing inert zirconia and produced a product of high diffusivity.

The resulting hydrogel beads were then aged for 20' hours at roomitemperature in Water and then for 24 hours at 200 F. in 1 percentaqueous H 804 solution resulting in a final hydrogel pH of 3.0. Thehydrogel after such treatment was base-exchanged with 2 percent byweight aqueous ammonium chloride solution, water washed freeof chlorideion, dried 16 hours at 270280 F. in air and] calcined hours at 1000 F.in air. The silica-zirconi'a' gel base so obtained was characterized bya pore volume of 0.40 cc./g.; an apparent density of 0.83 g./cc.; asurface area of 355' mP/g. and a weight composition of 0.01 percent Na,0'.10 percent S0 33.2 percent ZrO and remainder SiO Molybdena wasdeposited on the silica-zirconiabeads followed by calcination in air at1000 F. for 3 hours and sulfiding as in Example 4. The finished catalysthad a density of 0.99 g./cc., a surface area of 208 mP/g. and contained2.7 weight percent 000, 5.59 weight percent molybdenum and 3.72 weightpercent sulfur.

Hydrocracking 650 F. to tar West Texas gas oil with this catalyst at2000 p.s.i.g., l LHSV: 14,500 s.c.f./bbl. H circulation to 70 volumepercent conversion required a reactor temperature of 855 F. At theseconditions, the catalyst produced, as will be seen from Table I hereinbelow, 3.5 weight percent dry gas, 110.8 volume percent C.,+ product,consuming 1300 s.c.f./bb1. H The heavy naphtha to fuel oil ratio was0.72. The fuel oil had a diesel index of 40.

EXAMPLE 9 'ized by a pore volume of 0.44 cc./g.; an apparent density of0.80 g./cc.; a surface area of 327 m. g. and a weight composition of0.01 percent Na, 0.10 percent $0 32.5

' percent Zr0 and remainder SiO Platinum was deposited on 265 grams ofthe silicazirconia gel base by vacuum spray impregnating with 0.51percent Pt as an aqueous chloroplatinic acid solution made up of 14.81cc. of H PtCl containing 0.09 g. Pt/cc. diluted with water to a volumeof 117 cc. The resulting impregnated sample was Wet aged 16 hours at 230F. in a covered container, followed by reduction with hydrogen for 2hours at 450 F. and 2 hours at 950 F.

Hydrocracking with this catalyst using the charge stock and reactionconditions specified in previous examples required a reactor temperatureof 835 F. At these conditions, the catalyst produced 3.5 weight percentdry gas while making 110.1 volume percent C product. The product heavynaphtha to fuel oil ratio was 0.79. The diesel index of the heavynaphtha was 49.

Examples 10 and 11 illustrate the preparation of active and selectivehydrocrackiug catalysts wherein the particularly preparedsilica-zirconia base is impregnated respectively with nickel-tungstenand nickel-molybdena.

EXAMPLE 10 The catalyst of this example was prepared by impregnating. asilica-zirconia cogel base containing 89 weight percent SiO and 11weight percent ZrO with 7.5 weight percent Ni and 13 weight percent W.

The silica-zirconia base was prepared by mixing dilute N-Brand sodiumsilicate with an acid-zirconium sulfate solution to yield a hydrosolhaving a pH of 8.2 which set to a firm hydrogel in 2-3 seconds. Theresulting sol by vacuum spray impregnating with. 10. percent.M0O as awater solutionof molybdic acid, drying 16 hours at 230 F. and calciningshows at 1000 F. in air. This calcined.

sample was then impregnated with 3 percent CoO' as a water solution ofcobalt nitrate, dried 16 hours at 230 F.

was formed into beads by introducing the sol in the form of globulesinto a water-immiscible oil wherein the globules set to hydrogel beads.The'resulting hydrogel particles were aged inwater for 4 hours at roomtemperature and thereafter in 2 weight percent aqueous sulfuric acidsolution for 20 hoursat 200 F. reducing the hydrogel pH to 2.3. Thehydrogel, so activated, was then base-exchanged 8 times at two hourintervals with 2 weight percent aqueous ammonium sulfate solution,washed sulfate free with water and dried at 250-300 F.

The dried silica-alumina base was vacuum impregnated with an aqueousnickel nitrate solution to deposit 7.5 weight percent nickel, soaked 24hours at room temperature, dried 16 hours at 240 F. and activated bycalcining from 200 F. to 925 F. in air. The calcined composite, aftercooling, was reimpregnated with 13 weight percent tungsten, employing anaqueous ammonium tungstate solution.

The product Was then treated for 3 hours at 1000 F. with air flowing ata rate of 5 volumes per volume of product per minute and thereafter withan equal volume mixture of hydrogen and hydrogen sulfide for 5 hours at800 F. utilizing 2 volumes of gaseous mixture per volume of product perminute.

The treated product was cooled in nitrogen. The

sulfur content of the finished catalyst was 6.5 weight percent.

EXAMPLE 11 The catalyst of this example was prepared using the same baseas in Example 10 except that such base was calcined, prior toimpregnation, for 3 hours at 1300 F.

in air.

The calcined base was then vacuum impregnated content of the finishedcatalyst was 5.5 percent by weight.

Catalytic evaluations of the above catalysts of Examples 10 and 11 withWest Texas 650 F. to tar gas oil at 2000 p.s.i.g.; 1 LHSV; 14,500s.c.f./bbl. H are summarized in Table I.

Referring to such data, it is seen 0 that the dehydrogenation componentsof nickel-tungsten and nickel-molybdena in combination with theparticularly prepared silica-zirconia base afforded active and selectivehydrocracking catalysts. These catalysts rc- Table quired respectively825 F. and 828 F. reactor temperature for volume percent conversion ofthe gas oil charge to products boiling 650 F.

The following example illustrates the preparation of 5 an activehydrocracking catalyst prepared by depositing nickel alone on theparticularly prepared silica-zirconia base.

The catalyst of this example was prepared by impregnation of asilica-zirconia base formed at 8.3 pH, activated in a 2 weight percentaqueous sulfuric acid solution for 24 hours at 200 F. and thereafterprocessed in a manner similar to that described in Example 1. Theactivated silica-zirconia base (189.6 grams) was impregnated with 127ppm. of nickel, employing 94 cc. of an aqueous EXAMPLE 12 solution ofnickel nitrate.

The impregnated product was dried for 16 hours at 230 F. and thencalcined in air for 3 hours at 1000 The finished catalyst contained, ona dry basis, 12? ppm. of nickel and had a surface area of 613 in. /g.and an apparent density of 0.72 g./cc.

The above catalyst was evaluated for hydrocracking activity by treatinga Mid-Continent 650 F.+ gas oil at 2000 p.s.i.g.; 0.5 LHSV; 3000s.c.f./bbl. H obtained are summarized in Table I hereinbelow. Referenceto such data show that the catalyst is capable of affording about 81.7volume percent conversion of the charge with a good product distributionat 877 F. after 2.7 days on stream.

The above results, as well as those obtained upon testing the catalystsof Examples 1-11 for hydrocracking characteristics are shown below inTable I.

The data Example Catalyst composition:

000, percent Weight Mo, weight percent Sulfur, percent weight;

Pt, percent. Weight...

Cl, percent weight Catalyst properties:

Surface area, m /g Density, g./cc

orming pH Activation:

Room temp 24 hrs. H2O 16 hrs rs Solution 1% H2SO4. No H2O 27 112304.-."1% H2504"..- Time, hrs 24 2 24 24 Temp., F 175 200 Wet bulb, 220 175 200178-184 dry bulb. Properties:

Pore vol. ce./g 0.46... App. dens, g./ 0.63 Surface area, ruJ/g 589 490Composition:

Na, percent Weight 0.01 0.03 0.06 S04, percent weight 0.09 0 10 ZrOz,percent Weight 11.0.

Catalytic conversion of gas oil 1 (2,000 p.s.i.g., 1 L -65 products 24hrs. H2O. No.

2. 200 Wet bulb, 220

dry bulb.

%SV, 14,500 SOF/bbl. H3 circulation to 70 vol. percent 0 Reactor temp, F81 Dry gas, weight percent Total (Dis, Vol. percent--- Total 055, vol.perccut Light naphtha, vol. percent.

Heavy naphtha, vol. percent Lt. fuel oil, vol. percent Hvy. noph/fueloil vol. per t r r., A

Lt. fuel oil, 390650 F.:

Gr., API Die el index Sulfur, weight percent Heavy fuel oil:

Gr., APT

Nitrogen, weight per t Sulfur, Weight percent Table ICont1n ued p e 7 s9 10 11 12 Catalyst composition:

COO, percent weight 2.7 2.7 Ni 7 5 Ni 6 9 N1 127 p.p.m. Mo, weightpercent 6.45... 5.50.. W 1% Mo 6.60 Sulfur, percent weight-. 5.26.-3.72.- S 6.5.- S 5.5.. Pt, percent weight 0.51-. Cl, percent weight0.1-. Catalyst properties:

Surface area, mF/g. 471 208 Q15 Density, g./cc 0.72 0.99 0.84.- Basedescription:

Forming D 6.3-- 7.67 9 7.67 0 8.2-- Activation:

Room temp 24 hrs. H20... 24 hrs. H"... 1 hr. HO...-- 4 hrs. at 3.1...Solution HQSO; 1% H2304 1% H2804 2% H2804 Time, hrs 48 24 94 20 Temp, F200 200 200 200 00- Properties:

Pore vol. ccJE 0.54.-. 0.40.- 0.44.. 0.44.-. 0.40 0.45. App. dens, g./cc0.03..- 0.83.- 0.80.- .73. Surface area, Ind/g 597 255 327 6 57 6 12.Composition:

Na, percent weight- 0.01... 0.01.- 0.01.- 0.05. S04, percent weight 0.0l0.10 0.10.. 0. 9 Zr r, p rcent weight 11.1 33.2--- 32.5-- 11.9.-. 11.9--10.5.

Catalytic conversion of gas oil 1 (2,000 p.s.i.g., 1 LHSV, 14,500SOF/bbl. H2 circulation to 70 vol. percent (100-650 F. products Reactortemp, F..- 8 8 8 R 8 877. Dry gas, weight percent 3.5.... 3.5... 3.5..3.0.- 3.0.. 10.4. Total Crs, vol. percent.. 4.9.- 4.0.. 3.5.. 4.5..6.3-... 19.1. Total C s, vol. percent- 12.3. Light naphtha, vol. percent6.6. Heavy naphtha, vol. percent 28.3. Lt. fuel oil, vol. percent 23.0.Hvy. naph/iuel oil vol. percent 1.23. 04 plus product, vol. percent107.7. Hz consumption, SCF/bbl 1,342. Product quality:

Heavy N aph, ISO-390 F r., API 50 50 Lt. fuel oil, 390650 F:

Gr., API 3% 33 35.5.- Dicscl index. 41. 40 49 49. Sulfur, Weight percent0.02.- Heavy fuel oil:

Gr., API- 36 35. 35.5... Nitrogen, weight percent 0.002.. Suliur, weightpercent 0.01...

1 329. Texas Gas Oil having a boiling range of 650 F. to 92.5% at Mid-Continent 050 F. plus gas oil charge, 2,000 srgi, 0.5 LHSV, 3,000SCF/bbl. H2.

8 62 vol. percent conversion, 1.8 days on stream.

As will be seen from the above data, hydrocracking catalysts having adehydrogenation component deposited on the silica-zirconia gel baseprepared in the particular manner described herein are far more active,stable and selective in hydrocracking a heavy gas oil charge thancatalysts produced using a silica-zirconia base prepared at conditionsoutside those specified in accordance with the present invention.Catalysts prepared in accordance with the method described herein arecharacterized by good activity and stability producing unexpectedly highyields of C products with little dry gas. The heavy naphtha to fuel oilratios of the products formed established good gasoline productionproperties for the catalyst of the invention.

it will be understood that the above description is merely illustrativeof preferred embodiments of the invention, of which many variations maybe made by those skilled in the art without departing from the spiritthereof.

We claim:

1. A process for hydrocracking a hydrocarbon charge which comprisescontacting the same in the presence of hydrogen at a temperature betweenabout 600 F. and about 1050 F., at a liquid hourly space velocitybetween about 0.1 and about 10', a hydrogen partial pressure betweenabout 100 and about 5000 pounds per square inch gauge employing a molarratio of hydrogen to hydrocarbon charge between about 2 and about 80with a catalyst composed of a dehydrogenation component deposited on abase consisting essentially of silica and zirconia having a zirconiacontent of between about 2 4 56.3 vol. percent conversion, 2.9 days onstream. 6 81.7 vol. percent conversion.

8 Catalyst unstable-no balance run possible.

1 25% conversion; total product 26 API.

water-soluble zirconium compound and an alkali metal silicate to efiectformation of a gelable sol consisting essentially of silica and zirconiacharacterized by a pH in excess of 6 and a zirconia content, on a drybasis, of between about 2 and about 20, permitting said sol to setforming a silica-zirconia gel, reducing the pH of said gel to below 5and maintaining the gel under such conditions of reduced pH while incontact with an aqueous medium at a temperature in the approximate rangeof 150 to 220 F. for a period of at least about 1 hour under conditionsof substantially atmospheric pressure, thereafter washing the gel freeof soluble matter, drying and calcining.

2. A process for hydrocracking a hydrocarbon charge which comprisescontacting a hydrocarbon fraction having an initial boiling point of atleast about 400 F., a 50 percent point of at least about 500 F. and anend point of at least about 600 F. and boiling substantiallycontinuously between said initial boiling point and said end point inthe presence of hydrogen at a temperature between about 600 F. and about1050 F., at a liquid hourly space velocity between about 0.1 and about10, a

. hydrogen partial pressure between about 100 and about 5000 pounds persquare inch gauge employing a molar ratio of hydrogen to hydrocarboncharge between about 2 and about 80 with a catalyst composed of adehydrogenation component deposited on a base consisting essentially ofsilica and zirconia having a zirconia content of between about 2 andabout 20 percent by weight, prepared by reacting a water-solublezirconium compound and an and about 20 percent by weight, prepared byreacting a alkali metal silicate to effect formation of a gelable solconsisting essentially of silica and zirconia characterized by a pH inexcess of 6 and a zirconia content, on a dry basis, of between about 2and about 20 permitting said sol to set forming a silica-zirconia gel,reducing the pH of said gel to below and maintaining the gel under suchconditions of reduced pH while in contact with an aqueous medium at atemperature in the approximate range of 150 to 220 F. for a period of atleast about 1 hour under conditions of substantially atmosphericpressure, thereafter washing the gel free of soluble matter, drying andcalcining.

3. A process for hydrocracking a hydrocarbon charge which comprisescontacting the same in the presence of hydrogen at a temperature betweenabout 600 F. and about 1050 F., at a liquid hourly space velocitybetween about 0.1 and about 10, a hydrogen partial pressure betweenabout 100 and about 5000 pounds per square inch gauge, employing a molarratio of hydrogen to hydrocarbon charge between about 2 and about 80with a catalyst composed of a dehydrogenation component deposited on abase consisting essentially of silica and zirconia having a zirconiacontent of between about 2 and about 20 percent by weight, prepared byreacting a water-soluble zirconium compound and an alkali metal silicatehaving dispersed therein between about 2 percent and about 40 percent byweight of the dried base of a solid powdered material characterized byinsolubility in the resulting hydrosol, infusibility at the temperatureof calcination of the resulting base and a weight mean particle diameterof between about 1 and about 5 microns to effect formation of a gelablesol consisting essentially of silica and zirconia characterized by a pHin excess of 6 and a zirconia content, on a dry solids basis, of betweenabout 2 and about 20 percent by weight, permitting the said sol to setforming a gel consisting essentially of silica and zirconia, reducingthe pH of said gel to below 5 and maintaining the gel under suchconditions of reduced pH while in contact with an aqueous medium at atemperature in the approximate range of 150 to 220 F. for a period of atleast about 1 hour under conditions of substantially r atmosphericpressure, thereafter Washing the gel free of soluble matter, drying andcalcining.

4. A process for hydrocracking a hydrocarbon charge which comprisescontacting the same in the presence of hydrogen at a temperature betweenabout 600 F. and about 1050 F., at a liquid hourly space velocitybetween about 0.1 and about 10, a hydrogen partial pressure betweenabout 100 and about 5000 pounds per square inch gauge employing a molarratio of hydrogen to hydrocarbon charge between about 2 and about 80with a catalyst comprising a minor proportion of a dehydrogenationcomponent selected from the group consisting of a metal, an oxide of ametal and a sulfide of a metal of groups V, VI and VIII of the periodictable deposited on a base consisting essentially of silica and zirconiahaving a zirconia content of between about 2 and about 20 percent byweight, prepared by reacting a water-soluble zirconium compound and analkali metal silicate to effect formation of a gelable sol consistingessentially of silica and zirconia characterized by a pH in excess of 6and a zirconia content, on a dry basis, of between about 2 and about 20,permitting said sol to set forming a silicazirconia gel, reducing the pHof said gel to below 5 and maintaining the gel under such conditions ofreduced pH while in contact with an aqueous medium at a temperature inthe approximate range of 150 to 220 F. for a period of at least about 1hour under conditions of substantially atmospheric pressure, thereafterwashing the gel free of soluble matter, drying and calcining.

5. A process for hydrocracking a hydrocarbon charge which comprisescontacting the same in the presence of hydrogen at a temperature betweenabout 600 F. and about 1050 F., at a liquid hourly space velocitybetween about 0.1 and about 10, a hydrogen partial pressure betweenabout 100 and about 5000 pounds per square inch gauge, employing a molarratio of hydrogen to hydro carbon charge between about 2 and about witha catalyst comprising a minor proportion of molybdena deposited on asilica-zirconia base, said base having a zirconia content of betweenabout 2 and about 20 percent by weight and prepared by reacting awater-soluble zirconium compound and an alkali metal silicate to effectformation of a gelable sol consisting essentially of silica and zirconiacharacterized by a pH in excess of 6 and a zirconia content, on a drybasis, of between about 2 and about 20, permitting said sol to setforming a silicazirconia gel, reducing the pH of said gel to below 5 andmaintaining the gel under such conditions of reduced pH while in contactwith an aqueous medium at a temperature in the approximate range of 150to 220 F. for a period of at least about 1 hour under conditions ofsubstantially atmospheric pressure, thereafter washing the gel free ofsoluble matter, drying and calcining.

6. A process for'hydrocracking a hydrocarbon charge which comprisescontacting the same in the presence of hydrogen at a temperature betweenabout 600 F. and about 1050 F., at a liquid hourly space velocitybetween about 0.1 and about 10, a hydro-gen partial pressure betweenabout and about 5000 pounds per square inch gauge, employing a molarratio of hydrogen to hydrocarbon charge between about 2 and about 80with a catalyst comprising a minor proportion of nickel deposited on asilica-zirconia base, said base having a zirconia content of betweenabout 2 and about 20 percent by Weight and prepared by reacting awater-soluble zirconium compound and an alkali metal silicate to effectformation of a gelable sol consisting essentially of silica and zirconiacharacterized by a pH in excess of 6 and a zirconia content, on a drybasis, of between about 2 and about 20, permitting said sol to setforming a silicazirconia gel, reducing the pH of said gel to below 5 andmaintaining the gel under such conditions of reduced pH while in contactwith an aqueous medium at at temperature in the approximate range of to220 F. for a period of at least about 1 hour under conditions ofsubstantially atmospheric pressure, thereafter washing the gel free ofsoluble matter, drying and calcining.

7. A process for hydrocracking a hydrocarbon charge which comprisescontacting the same in the presence of hydrogen at a temperature betweenabout 600 F. and about 1050 F., at a liquid hourly space velocitybetween about 0.1 and about 10, a hydrogen partial pressure betweenabout 100 and about 5000 pounds per square inch gauge, employing a molarratio of hydrogen to hydrocarbon charge between about 2 and about 80with a catalyst consisting essentially of a minor proportion of platinumdeposited on a silica-zirconia base, said base having a zirconia contentof between about 2 and about 20 percent by weight and prepared byreacting a water-soluble zirconium compound and an alkali metal silicateto effect formation of a gelable sol consisting essentially of silicaand zirconia characterized by a pH in excess of 6 and a zirconiacontent, on a dry basis, of between about 2 and about 20, permittingsaid sol to set forming a silicazirconia gel, reducing the pH of saidgel to below 5 and maintaining the gel under such conditions of reducedpH while in contact with an aqueous medium at a temperature in theapproximate range of 150 to 220 F. for a period of at least about 1 hourunder conditions of substantially atmospheric pressure, thereafterwashing the gel free of soluble matter, drying and calcining.

8. A process for hydrocracking a hydrocarbon charge which comprisescontacting the same in the presence of hydrogen at a temperature betweenabout 600 F. and about 1050 F., at a liquid hourly space velocitybetween about 0.1 and about 10, a hydrogen partial pressure be tweenabout 100 and about 5000 pounds per square inch gauge, employing a molarratio of hydrogen to hydro-v carbon charge between about 2 and about 80with a catalyst consisting essentially of a minor proportion ofmolybdenum oxide and cobalt oxide deposited on a silicazirconia base,said base having a zirconia content of between about 2 and about 20percent by weight and prepared by reacting a water-soluble zirconiumcompound and an alkali metal silicate to effect formation of a gelablesol consisting essentially of silica and zirconia characterized by a pHin excess of 6 and a zirconia content, on a dry basis, of between about2 and about 20, permitting said sol to set forming a silica-zirconiagel, reducing the pH of said gel to below and maintaining the gel undersuch conditions of reduced pH while in contact with an aqueous medium ata temperature in the approximate range of 150 to 220 F. for a period ofat least about 1 hour under conditions of substantially atmosphericpressure, thereafter washing the gel free of soluble matter, drying andcalcining.

9. A process for hydroeracking a hydrocarbon charge which comprisescontacting the same in the presence of hydrogen at a temperature betweenabout 600 F. and about 1050 F., at a liquid hourly space velocitybetween about 0.1 and about 10, a hydrogen partial pressure betweenabout 100 and about 5000 pounds per square inch gauge, employing a molarratio of hydrogen to hydrocarbon charge between about 2 and about 80with a catalyst consisting essentially of a minor proportion of nickeland molybdenum oxide deposited on a silica-zirconia base, said basehaving a zirconia content of between about 2 and about 20 percent byweight and prepared by reacting a water-soluble zirconium compound andan alkali metal silicate to elfect formation of a gelable sol consistingessentially of silica and zirconia characterized by a pH in excess of 6and a zirconia content, on a dry basis, of between about 2 and about 20,permitting said sol to set forming a silica-zirconia gel, reducing thepH of said gel to below 5 and maintaining the gel under such conditionsof reduced pH while in contact with an aqueous medium at a temperaturein the approximate range of 150 to 220 F. for a period of at least about1 hour under conditions of substantially atmospheric pressure,thereafter washing the gel free of soluble matter, drying and calcining.

10. A process for hydrocracking a hydrocarbon charge which comprisescontacting the same in the presence of hydrogen at a temperature betweenabout 600 F. and about 1050 F., at a liquid hourly space velocitybetween about 0.1 and about 10, a hydrogen partial pressure betweenabout 100 and about 5000 pounds per square inch gauge, employing a molarratio of hydrogen to hydrocarbon charge between about 2 and about 80with a catalyst consisting essentially of a minor proportion of nickeland tungsten deposited on a silica-zirconia base, said base having azirconia content of between about 2 and about 20 percent by weight andprepared by reacting a water-soluble zirconium compound and an alkalimetal silicate to effect formation of a gelable sol consistingessentially of silica and zirconia characterized by a pH in excess of 6and a zirconia content, on a dry basis, of between about 2 and about 20,permitting said sol to set forming a silica-zirconia gel, reducing thepH of said gel to below 5 and maintaining the gel under such conditionsof reduced pH while in contact with an aqueous medium at a temperaturein the approximate range of 150 to 220 F. for a period of at least about1 hour under conditions of substantially atmospheric pressure,thereafter washing the gel free of soluble matter, drying and calcining.

11. A hydrocarbon conversion catalyst consisting essentially of a minorproportion of a dehydrogenation component selected from the groupconsisting of a metal, an oxide of a metal and a sulfide of a metal ofgroups V, VI and VIII of the periodic table deposited on asilicazirconia base having a zirconia content of between about 2 andabout 20 and prepared by reacting a water-soluble zirconium compound andan alkali metal silicate to effect formation of a gelable sol consistingessentially of silica and zirconia characterized by a pH in excess of 6and a zirconia content, on a dry basis, of between about 2 and about 20,permitting said sol to set forming a silicazirconia gel, reducing the pHof said gel to below 5 and maintaining the gel under such conditions ofreduced pH while in contact with an aqueous medium at a temperature inthe approximate range of 150 to 220 F. for a period of at least about 1hour under conditions of substantially atmospheric pressure, thereafterwashing the gel free of soluble matter, drying and calcining.

12. A hydrocarbon conversion catalyst consisting essentially of betweenabout 2 and about 20 percent by weight of molybdena deposited on asilica-zirconia base having a zirconia content of between about 2 andabout 20 and prepared by reacting a water-soluble zirconium compound andan alkali metal silicate to effect formation of a gelable sol consistingessentially of silica and zirconia characterized by a pH in excess of 6and a zirconia content, on a dry basis, of between about 2 and about20,- permitting said sol to set forming a silica-zirconia gel, reducingthe pH of said gel to below 5 and maintaining the gel under suchconditions of reduced pH while in contact with an aqueous medium at atemperature in the approximate range of 150 to 220 F. for a period of atleast about 1 hour under conditions of substantially atmosphericpressure, thereafter washing the gel free of soluble matter, drying andcalcining.

13. A hydrocarbon conversion catalyst consisting essentially of betweenabout 0.05 and about 10 percent by weight of platinum deposited on asilica-zirconia base having a zirconia content of between about 2 andabout 20 and prepared by reacting a water-soluble zirconium compound andan alkali metal silicate to effect formation of a gelable sol consistingessentially of silica and zirconia characterized by a pH in excess of 6and a zirconia content, on a dry basis, of between about 2 and about 20,permitting said sol to set forming a silicazirconia gel, reducing the pHof said gel to below 5 and maintaining the gel under such conditions ofreduced pH while in contact with an aqueous medium at a temperature inthe approximate range of 150 to 220 F. for a period of at least about 1hour under conditions of substantially atmospheric pressure, thereafterwashing the gel free of soluble matter, drying and calcining.

14. A hydrocarbon conversion catalyst consisting essentially of betweenabout 1 and about 10 percent by weight of cobalt oxide and between about1 and about 20 percent by weight of molybdenum oxide deposited on asilica-zirconia base having a zirconia content of between about 2 andabout 20 and prepared by reacting a watersoluble zirconium compound andan alkali metal silicate to effect formation of a gelable sol consistingessentially of silica and zirconia characterized by a pH in excess of 6and a zirconia content, on a dry basis, of between about 2 and about 20,permitting said sol to set forming a silicazirconia gel, reducing the pHof said gel to below 5 and maintaining the gel under such conditions ofreduced pH while in contact with an aqueous medium at a tempera ture inthe approximate range of 150 to 220 F. for a period of at least about 1hour under conditions of substantially atmospheric pressure, thereafterwashing the gel free of soluble matter, drying and calcining.

15. A hydrocarbon conversion catalyst consisting essentially of betweenabout .01 and about 10 percent by weight of nickel and about 1 and about20 percent by weight of molybdenum oxide deposited on a silica-zirconiabase having a zirconia content of between about 2 and about 20 andprepared by reacting a water-soluble zirconium compound and an alkalimetal silicate to eifect formation of a gelable sol consistingessentially of silica and zirconia characterized by a pH in excess of 6and a zirconia content, on a dry basis, of between about 2 and about 20,permitting said sol to set forming a silicazirconia gel, reducing the pHof said gel to below 5 and maintaining the gel under such conditions ofreduced pH stantially atmospheric pressure, thereafter washing the gelfree of soluble matter, 'drying and calcining.

16. A hydrocarbon conversion catalyst consisting essentiallyof betweenabout .01 and about 10 percent by weight of nickel and about 1 and about20 percent by weight of tungsten deposited on a silica-zirconia basehaving a zirconia content of between about 2 and about 20 and preparedby reacting a water-soluble zirconium compound and an alkali metalsilicate'to effect formation of a gelable sol consisting essentially ofsilica and zirconia characterized .by a pH in excess of 6 and a zirconiacontent, on a dry basis, of between about 2 and about 20, permittingsaid sol to set forming a silica-zirconia gel, reducing the pH of saidgel to below 5 and maintaining the gel under such conditions of reducedpH While in contact with an aqueous medium at a temperature in theapproximate range of 150 to 220 F. fora period of at least about 1 hourunder conditions of substantially atmospheric pressure, thereafterwashing the gel free of soluble matter, drying and calcining.

'17. Ahydrocarbon conversion catalyst consisting essen- V tially of aminor proportion of a dehydrogenation component selected from the groupconsisting of a metal, an oxide of a metal and a sulfide of a metal ofgroups V, VI and VIII of the periodic table deposited on a silicia-"zirconia base having a zirconia content, of between about 2 an'd about20 percent by weight and prepared by reacting a water-soluble zirconiumcompound and an alkali metal silicate having dispersed therein betweenabout 2 and about 40 percent by weight of the dried base of a solidpowdered material characterized by insolubility in the resultinghydrosol, infusibility at the temperature of calcination of theresulting base, and a weight mean particle diameter of between about 1and about 5 microns to effect formation of a gel-able sol comprisingsilica and zirconia characterized by a pH in excess of 6 and a zirconiacontent, on a dry basis, of between about 2 and about 20 percent byweight, permitting the said sol to set forming a gel consistingessentially of silica and zirconia, reducing the pH of said gel to below5 and maintaining the gel under such conditions of reduced pH while incontact with an aqueous medium at a temperature in the approximate rangeof 150 to 220 F. for a period of at least about '1 hour under conditionsof substantially atmospheric pressure, thereafter washing the gel freeof soluble matter,

drying and calcining.

18. A method for preparing a catalytic composite which comprisesreacting in aqueous solution a water-soluble zirconium compound and analkali metal silicate to effect formation of a gelable sol consistingessentially of silica and zirconia characterized by a pH in excess of 6and a zirconia content, on a dry basis, of between about 2 and about 20,permitting said sol to set forming a silicazirconia gel, reducing the pHof said gel to below 5 and maintaining the gel under such conditions ofreduced pH while in contact with an aqueous medium at a temperature inthe approximate range of 150 to 220* F. for a period of-at least about 1hour under conditions of substantially "2d atmospheric pressure, washingthe gel free of soluble matter, drying, calcining, and depositing on theresulting silicazirconia gel a minor proportion of a dehydrogenationcomponent selected from the group consisting of a metal, an oxide of ametal, and a sulfide of a metal of groups V, VI and VIII of the periodictable.

19. A method for preparing spheroidal particles of a hydrocrackingcatalyst which comprises reacting in aqueous solution, a water-solublezirconium compound and an alkali metal silicate to effect formation of agelable sol consisting essentially of silica and zirconia characterizedby a pH in excess of 6 but not greater than 10, a gelation time of lessthan 20 seconds, and a zirconia content, on a dry basis, of betweenabout 2 and about 20 percent by weight, introducing globules of theresulting hydrosol into a water-immiscible fluid wherein the globules ofhydrosol set to spheroidal particles of hydrogel, effecting gelation ofsaid spheroidal hydrosol particles, reducing the pH of said particles tobelow 5 but in excess of 1 and maintaining the hydrogel particles undersuch conditions of reduced pH while in contact with an aqueous acidicmedium at a temperature in the approximate range of 175 to 220 F. for atleast about 1 hour under conditions of substantially atmosphericpressure, water-washing the gel free of soluble matter, drying,calcining and depositing on the resulting spheroidal silica-zirconia gela minor proportion of a dehydrogenation component selected from thegroup consisting of a metal, an oxide of a metal, and a sulfide of ametal of groups V, VI and VIII of the periodic table.

20. A method for preparing a catalytic composite which comprisesreacting a water-soluble zirconium compound and an alkali metal silicatehaving dispersed therein between about 2 percent and about 4-0 percentby weight of the dried gel of a solid powdered material characterized byinsolubility in the resulting hydrosol, infusibility at the temperatureof calcination of the resulting gel and a weight mean particle diameterof between about 1 and about 5 microns to effect formation of a gelablesol consisting essentially of silica and zirconia characterized by a pHin excess of 6 and a zirconia content, on a dry basis, of between about2 and about 20 percent by weight, permitting the said sol to set forminga gel comprising silica and zirconia, reducing the pH of said gel tobelow 5 and maintaining the gel under such conditions of reduced pHwhile in contact with an aqueous medium at a temperature in theapproximate range of 150 to 220 F. for a period of at least about 1 hourunder conditions of substantially atmospheric pressure, washing the gelfree of soluble matter, drying, calcining, and depositing on theresulting silica-zirconia gel a minor proportion of a dehydrogenationcomponent selected from the group consisting of a metal, an oxide of ametal, and a sulfide of a metal of groups V, VI and VIII of the periodictable.

Bates et al Jan. 1, 1952 Johnson et al July 16, 1957 UNITED STATESPATENT OFFICE CERTIFICATE OF QORRECTION Patent N0o 3,067,127 December 4,1962 Charles J Plank et al It is hereby certified that error appears inthe above numbered pat- I ent requiring correction and that the saidLetters Patent should read as corrected below.

Column 3, line 42, for "usually" read unusually -5 line 47, for"above-described desirable" read aboveindicated desirable column 9 line41, for "hot acid' read hot aqueous acid --;3 column l0 line 56, for"activated hydrogen" read activated hydrogel -3 column 11, line 56 for"hydrogen" read hydrogel line 74, for 6.25 read 626 5 columns 17 and 18Table l third column, line 10 thereof, for "l H 50 read 1% H 50 Signedand sealed this 21st day of May 1963.,

. (SEAL) Attest:

1 ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner ofPatents

1. A PROCESS FOR HYDROCRACKING A HYDROCARBON CHARGE WHICH COMPRISES CONTACTING THE SAME IN THE PRESENCE OF HYDROGEN AT A TEMPERATURE BETWEEN ABOUT 600*F. AND ABOUT 1050*F., AT A LIQUID HOURLY SPACE VELOCITY BETWEEN ABOUT 0.1 AND ABOUT 10, A HYDROGEN PARTICAL PRESSURE BETWEEN ABOUT 100 AND ABOUT 5000 POUNDS PER SQUARE INCH GAUGE EMPLOYING A MOLAR RATIO OF HYDROGEN TO HYDROCARBON CHARGE BETWEEN ABOUT 2 AND ABOUT 80 WITH A CATALYST COMPOSED OF A DEHYDROGENATION COMPONENT DEPOSITED ON A BASE CONSISTING ESSENTIALLY OF SILICA AND ZIRCONIA HAVING A ZIRCONIA CONTENT OF BETWEEN ABOUT 2 AND ABOUT 20 PERCENT BY WEIGHT, PREPARED BY REACTING A WATER-SOLUBLE ZIRCONIUM COMPOUND AND AN ALKALI METAL SILICATE TO EFFECT FORMATION OF A GELABLE SOL CONSISTING ESSENTIALLY OF SILICA AND ZIRCONIA CHARACTERIZED BY A PH IN EXCESS OF 6 AND A ZIRCONIA CONTENT, ON A DRY BASIS, OF BETWEEN ABOUT 2 AND ABOUT 20, PERMITTING SAID SOL TO SET FORMING A SILICA-ZIRCONIA GEL, REDUCING THE PH OF SAID GEL TO BELOW 5 AND MAINTAINING THE GEL UNDER SUCH CONDITIONS OF REDUCED PH WHILE IN CONTACT WITH AN AQUEOUS MEDIUM AT A TEMPERATURE IN THE APPROXIMATE RANGE OF 150 TO 220*F. FOR A PERIOD OF AT LEAST ABOUT 1 HOUR UNDER CONDITIONS OF SUBSTANTIALLY ATMOSPHERIC PRESSURE, THEREAFTER WASHING THE GEL FREE OF SOLUBLE MATTER, DRYING AND CALCINING. 